A spotter that includes a plurality of spotting heads, each of the plurality of spotting heads having a discharging portion at a tip portion, the plurality of spotting heads form an m×n array (m, n>1) with m spotting heads arranged lengthwise and n spotting heads arranged crosswise; and a pitch varying mechanism configured to vary an array pitch of the plurality of spotting heads arrayed in a lengthwise direction and an array pitch of the plurality of spotting heads arrayed in a crosswise direction.